(car) air bag; a safety device in a vehicle that inflates rapidly in the event of a collision

aerostat gasbag; a balloon or large envelope made of rubberized fabric filled with gas used to lift airships or weather balloons

an air-filled sac in birds, insects, or reptiles that assists with breathing and regulates body temperature or buoyancy

wing-like protrusions on the pollen grains of conifers that assist in wind dispersal